We are going to use Bootstrap 4 in Drupal 8/9 with Bootstrap Barrio. The Bootstrap Barrio theme for Drupal 8/9 integrates Bootstrap 4 (or Bootstrap 5 if you want) with your Drupal site. 

Bootstrap is a very popular framework for building websites. It provides designers and developers with a common language to communicate, making the development process a lot easier.

Creating a subtheme of Barrio is a straightforward process. This tutorial will explore the basic configuration options of the theme, which are managed through a complete graphical user interface.

Keep reading to learn how!